1. Field of the Invention
The invention relates to an information processing apparatus corresponding to a network, an information processing apparatus for controlling an external information processing apparatus, and a network system including those apparatuses.
2. Related Background Art
In association with the rapid spread of the Internet communication, network corresponding type devices are rapidly being progressed in a manner such that not only the conventional personal computers but also user-interactive devices such as PDA (Personal Digital Assistance), cellular phones, and the like, image processing apparatuses such as scanner, printer, copying apparatus, digital camera, and the like, and household appliances such as television, air-conditioner, refrigerator, and the like are made to correspond to networks.
In association with it, a network connecting procedure of the network corresponding type devices which has hitherto been made by a network administrator has been simplified. Particularly, with respect to IP address setting which is important in Internet protocol (IP) setting, in addition to the conventional manual setting, automatic allocation using a DHCP server or setting by automatic IP address obtaining means (which has been released by a document name “draft-ietf-zeroconf-ipv4-linklocal-01.txt” by IETF) for a network environment such as a SOHO (Small Office/Home Office) environment in which a server cannot be installed has been proposed. The above means is also used in Universal Plug and Play Device Architecture v1.0 proposed by Microsoft Corporation. Thus, the ordinary user can make communication using an IP address of the network corresponding type device mentioned above.
An ARP protocol has also been developed in order to solve problems of LAN addresses. For example, there is a technique such that if a certain peripheral device A broadcasts an IP address of an apparatus with which it wants to communicate to a predetermined network segment, a peripheral device B to which the IP address has been allocated returns a set of an MAC address and the IP address of the peripheral device B, so that the peripheral device A can communicate by using the MAC address after that.
However, there is a case where if the network corresponding type device is equipped with means for automatically obtaining the IP address by using the DHCP server, the automatic IP address obtaining means, or the like, the network corresponding type device executes a process for obtaining the IP address and obtains a different IP address each time the user participates in the network.
Therefore, the user needs to change a network configuration setting of application software, utility software, driver software, or the like for using the network corresponding type device installed into a client device each time he uses such software. There is also a problem such that unless the user uses a software tool or the like of the network, he cannot obtain the latest IP address of the network corresponding type device to be used, or the like. Even if communication is made by using the ARP protocol, an ARP table which each device possesses is not dynamically changed in accordance with a connecting state of a peripheral device as an example of external information processing apparatuses. To make proper communication, the user needs to make a complicated manual setting. As preferred examples of the peripheral devices of the invention, all types of network corresponding type devices are included, and the image processing apparatuses such as scanner, printer, copying apparatus, digital camera, and the like, the household appliances such as television, air-conditioner, refrigerator, and the like, and their hybrid apparatus can be mentioned. The peripheral devices are included in the information processing apparatus of the invention.
The DHCP server grasps the IP address which has been lent to the peripheral device, that is, the IP address of which temporary allocation has been allowed. However, the DHCP server does not have a mechanism for dynamically managing the clients by using the set of the MAC address as an example of fixed identification information which is fixedly allocated to the client and the IP address as an example of variable identification information which is variably allocated to it. The DHCP server is a server for lending the IP address and does not execute a process for discriminating the connecting state of the peripheral device with which it wants to communicate by using the set of the MAC address and the IP address.
When a network system in which a service management server for unitarily managing services is unnecessary is constructed, it is necessary that each device on the network manages network information. In order to enable the device to recognize which device is active on the network in such a network system, a method whereby when the device is disconnected from the network, the devices on the same network are notified of information indicative of its disconnection from the network in a broadcasting manner can be considered. However, at this time, there is a case where the devices on the network cannot normally receive the disconnection notification from the peripheral device to be disconnected from the network, so that a problem occurs. For example, there is a case where the peripheral device causes a system-down without making the disconnection notification or a case where before the disconnection notification from the peripheral device reaches other peripheral devices, another new peripheral device participates in the network and starts communication by using the identification information on the same network as that of the relevant peripheral device.